In the theory of judgment aggregation, it is known for which agendas of propositions it is possible to aggregate individual judgments into collective ones in accordance with the Arrow-inspired requirements of universal domain, collective rationality, unanimity preservation, non-dictatorship and...

According to standard rational choice theory, as commonly used in political science and economics, an agent''s fundamental preferences are exogenously fixed, and any preference change over decision options is due to Bayesian information learning. Although elegant and parsimonious, this model...

How can the propositional attitudes of several individuals be aggregated into overall collective propositional attitudes? Although there are large bodies of work on the aggregation of various special kinds of propositional attitudes, such as preferences, judgments, probabilities and utilities,...

Several recent results on the aggregation of judgments over logically connected propositions show that, under certain conditions, dictatorships are the only independent (i.e., propositionwise) aggregation rules generating fully rational (i.e., complete and consistent) collective judgments. A...

Standard impossibility theorems on judgment aggregation over logically connected propositions either use a controversial systematicity condition or apply only to agendas of propositions with rich logical connections. Are there any serious impossibilities without these restrictions? We prove an...

All existing impossibility theorems on judgment aggregation require individual and collective judgment sets to be consistent and complete (in some recent results with completeness relaxed to deductive closure), arguably a demanding rationality requirement. They do not carry over to aggregation...

We show that, when a group takes independent majority votes on interconnected propositions, the outcome is consistent once the profile of individual judgment sets respects appropriate structural conditions. We introduce several such conditions on profiles, based on ordering the propositions or...

In solving judgment aggregation problems, groups often face constraints. Many decision problems can be modelled in terms the acceptance or rejection of certain propositions in a language, and constraints as propositions that the decisions should be consistent with. For example, court judgments...

The standard rational choice paradigm explains an individual’s preferences by his beliefs and his fundamental desires. For instance, someone’s preference for joining the army might be explained by certain beliefs about what life in the army is like and a desire for such a life. While beliefs...

We consider the classical problem of opinion pooling: the probability assignments of different individuals are to be merged into collective probability assignments. While opinion pooling has been explored in some depth in the literature (by statisticians, economists, and philosophers), all...